Once we purchase this Rental Income Expense Tracker, do we get unlimited lifetime access to it or is it like a subscription that we need to pay every year?

Once you download it - you get unlimited lifetime access. You can use it year after year. There are no subscription fees.

What do I do for the new year, will I need to buy another Rental Tracking spreadsheet?

There is no need to buy another Rental Income & Expense Tracking spreadsheet. Just save a blank copy of the spreadsheet you downloaded and use it year after year for huge savings!

Does the 20 properties rental tracker have more options than the 10 properties tracker? 

The 20 properties tracker allows for sorting and filtering by any field in the Income section.

Also it has navigation buttons that allow you to quickly reach any property sheet from the dashboard.

Do you think the Rental Tracking spreadsheet is something one with no computer experience/older generation could use?

Basic experience with using a computer would definitely be required. That said, these spreadsheets have been designed so that they are very easy to use - an electronic version of pen and paper ledgers - except there is very little need to write/type and everything gets automatically calculated.

Does the info like rent or expenses need to be inputted manually in multiple locations?

You only need to enter your transactions in one place.
The Dashboard and all other areas get automatically updated.

I’m interested in buying one of your spreadsheets for rental expense and income. Is it necessary to have experience in Excel?